1. Field of the Invention
The present invention relates to a liquid crystal display device and a method of manufacturing the same.
2. Description of the Related Art
A typically employed liquid crystal display device is constructed by bonding two substrates on which an electrode pattern and an oriented film are formed by utilizing sealing resin or a setting property of UV resin. Various attempts have been made in order to maintain a space between the pair of upper and lower substrates, such as plastic bead spacers of a predetermined diameter provided between the substrates or a plurality of columnar spacers formed between the substrates.
In the latter case in which the columnar spacers are formed, there is a method in which a resist exclusive to the spacers is used. There is also disclosed a method in which colored layers 24a′ 24b′ are layered to form a columnar spacer 24′ as shown in FIG. 8A.
Properly speaking, in order to form the columnar spacer 24′ by layering the colored layers 24a′, 24b′, the colored layers 24a′, 24b′ have to be layered accurately as shown in FIG. 8A. However, due to a problem in exposure accuracy and the like, a sufficient overlap between colors may not be obtained in some cases as shown in FIGS. 8B and 8C. If the sufficient overlap cannot be obtained in this manner, an overlap area of the column differs to cause variations in column strengths and unevenness of a gap.
With the above problems in view, in order to obtain a sufficient overlap area between colors, setting a pattern of a lower colored layer 24a′ in a size based on exposure accuracy as shown in FIGS. 9A and 9B. In the drawing, a designates a maximum value of the sum of the exposure accuracies of the two layers 24a′, 24b′. In this case, even if the layers are displaced from each other as shown in FIG. 9C, the overlap area does not change. Therefore, the column strength does not change and display unevenness due to the unevenness of the gap is not caused either. Moreover, in order to secure a sufficient height of the column, three layers 24a′, 24b′, and 24c′ may be layered as shown in FIG. 10. In the drawing, α1 and α2 designate maximum values of the sum of exposure accuracies of two layers, respectively. As the same kind of method, there is art described in Japanese Patent Application Laid-open No. H09-120074, where a column is not square but circular unlike the columns shown in FIGS. 9A to 10 but the purpose is the same.
However, in the spacers in FIGS. 9A to 9C and 10 and H09-120074, an increase in an area of the lowermost layer 24a′ is absolutely necessary. As a result, the spacer requires a larger area in a pixel of a liquid crystal display element and a numerical aperture of the pixel may be reduced to cause a reduction in a transmittance.